Rate-Determining Enzymes of Metabolic Processes

Question 1

Glycolysis

Answer 1

Enzyme: Phosphofructokinase-1 (PFK-1)
Regulators: AMP +, fructose-2,6-BP+, ATP -, citrate -

Question 2

Gluconeogenesis

Answer 2

Enzyme: Fructose-1,6-bisphosphatase
Regulators: ATP +, AMP -, fructose-2,6-BP -

Question 3

TCA cycle

Answer 3

Enzyme: Isocitrate dehydrogenase
Regulators: ADP +, ATP -, NADH -

Question 4

Glycogen synthesis

Answer 4

Enzyme: Glycogen synthase
Regulators: Glucose +, insulin +, epinephrine -, glucagon -

Question 5

Glycogenolysis

Answer 5

Enzyme: Glycogen phosphorylase
Regulators: AMP +, epinephrine +, glucagon +, insulin -, ATP -

Question 6

HMP shunt

Answer 6

Enzyme: Glucose-6-phosphate dehydrogenase (G6PD)
Regulators: NADP+ +, NADPH -

Question 7

De novo pyrimidine synthesis

Answer 7

Enzyme: Carbamoyl phosphate synthetase II
Regulators:

Question 8

De novo purine synthesis

Answer 8

Enzyme: Glutamine-PRPP amidotransferase
Regulators: AMP -, IMP -, GMP -

Question 9

Urea cycle

Answer 9

Enzyme: Carbamoyl phosphate synthetase I
Regulators: N-acetylglutamate +

Question 10

Fatty acid synthesis

Answer 10

Enzyme: Acetyl-CoA carboxylase (ACC)
Regulators: Insulin +, citrate +, glucagon -, palmitoyl-CoA -

Question 11

Fatty acid oxidation

Answer 11

Enzyme: Carnitine acyltransferase I
Regulators: Malonyl-CoA -

Question 12

Ketogenesis

Answer 12

Enzyme: HMG-CoA synthase
Regulators:

Question 13

Cholesterol synthesis

Answer 13

Enzyme: HMG-CoA reductase
Regulators: Insulin +, thyroxine +, glucagon -, cholesterol -